beginning of what?
Metal tool use, obviously.
And what countries are you speaking of all through out south east asia? names please dont be vague
You want a list of the nations of Southeast Asia?
http://en.wikipedia.org/wiki/Southeast_Asia
Nope.2.Do you live in these said countries currently? how are these countries "all through out" south east asia using these chisel grind swords? as primary weapons? in place of a machete?
The swords would presumably be used for the normal sword tasks, killing or threatening folks and as ceremonial objects.
Asymmetrically ground agricultural choppers are much more common than weapons. Even in Japan.in place of a machete?

3. Where are you getting your information id like to check it out...
Start here:
http://www.vikingsword.com/ethsword/
Then get some books from either your local library or your favored online retailer.
Your local university should have free journal acess (JSTOR etc) if you really want to get into minutiae.